Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog

From: Andrew Jones
Date: Wed Nov 05 2014 - 05:26:59 EST


On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote:
>
> Hi,
>
> commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled by
> default") provided a way for the kernel to disable the hard lockup
> detector at runtime.
>
> I'm using it on ppc64 but notice some weird behaviour with the
> nmi_watchdog procfs variable. At boot, that the hard lockup
> detector appears to be enabled even when we disable it via
> watchdog_enable_hardlockup_detector(false):
>
> # cat /proc/sys/kernel/nmi_watchdog
> 1
>
> I have to echo 0 to it then echo 1 again to enable it.
>
> Anton

Hi Anton,

Yes, the nmi watchdog proc variables are currently a bit
confusing. Uli has posted a series to clear all that up
though. Please see

https://lkml.org/lkml/2014/10/17/340

drew
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